1. Field of the Invention
The present invention relates in general to internal combustion engines and more particularly to a hollow ceramic piston pin for attaching a piston to a connecting rod in an internal combustion engine.
2. Description of the Prior Art
In order to meet the increasing demand for a high output internal combustion engine, a hollow ceramic piston pin has recently been utilized with a view to reducing the weight of a piston assembly.
A problem of the hollow ceramic piston pin is that it is liable to break at a portion joined with a connecting rod. To solve this problem, it has been proposed to make the hollow ceramic piston pin partially thick-walled at the portion joined with the connecting rod and grind the inner circumferential surface of the thick-walled portion for thereby increasing the breaking strength at minimum increase of the weight as disclosed in Japanese Utility Model Provisional Publication No. 63-4465. However, the piston pin proposed by Japanese Publication cannot efficiently increase the breaking strength but requires a difficult grinding process leading to considerable increase in cost.